Fix PR, milestone and label functionality if issue unit is disabled (#2710)
* Fix PR, milestone and label functionality if issue unit is disabled or not assigned to user
* Fix multi-actions in PR page
* Change error message
* Fix comment update and delete functionality in PR
<div class="ui green active basic button issue-action" data-action="open" data-url="{{$.Link}}/status">{{.i18n.Tr "repo.issues.action_open"}}</div>
<div class="ui red active basic button issue-action" data-action="close" data-url="{{$.Link}}/status">{{.i18n.Tr "repo.issues.action_close"}}</div>
<div class="ui green active basic button issue-action" data-action="open" data-url="{{$.RepoLink}}/issues/status">{{.i18n.Tr "repo.issues.action_open"}}</div>
<div class="ui red active basic button issue-action" data-action="close" data-url="{{$.RepoLink}}/issues/status">{{.i18n.Tr "repo.issues.action_close"}}</div>
</div>
<div class="ui secondary filter menu floated right">